Medicinal preparation



Patented May 28, 1935 UNITED STATES 7 2,002,829 mrcmsr. PREPARATIONArnold E. Octet-berg, Rochester, Minn, assignor to The ChemicalFoundation, Incorporated, New York, N. Y., a corporation of Delaware NoDrawing. Original application May 28, 1929',

Serial No. 366,765.

Divided and this application April 21, 1933, Serial No. 667,194

3Claims.

This application is a division of mycopending application Serial No.366,765, filed May 28, 1929; upon which application Patent No. 1,908,176was granted May 9, 1933, for Process for making 5 a purified coal tarointment.

The object of my invention is the production of a purified coal-tarointment for the treatment of acute and subacute eczemas, andparticularly infantile eczemas.

The use of crude coal tar in the treatment of eczematous inflammationsof the skin, more particularly in cases of infantile eczema, has beenfound eflicacious in aifording prompt and striking relief, and-has beenwidely-adopted by specialists in dermatology. The use of crude coal tarin such cases has two notable objections: first, the tendency to causefolliculitis on the skin; and, second, its undesirable properties ofstickiness and staining.

My invention or discovery consists in the identification and isolationof the therapeutically active principle present in the crude tar and inthe separation of this active ingredient from the crude material and itsextraction as a clean and eflicient preparation free from theobjectionable characteristics inherent in its use in the crude form.

As is well known, crude coal tar is a highly complex and variablemixture of many organic compounds. By the present process, I separatethe crude coal tar into two fractions by distillation, as follows:

One liter of the crude coal tar is placed in a three-liter distillingflask and distilled by passing through the hot solution a rapid streamof steam until no more oil appears in the distillate. I discard thefraction consisting of black, viscous residual pitch and take the otherfraction which is volatile with steam at about C. at atmosphericpressure. This product I redistil'in the presence of steam to insure theremoval of any contaminating residual pitch which may'have been carriedover mechanically during the first distillation. The product is avolatile semi-solid ether-soluble oil which is next extracted with anyimmiscible organic solvent capable of dissolving ether-solublesubstances, and preferably with ethyl-ether. The ether-soluble productresultant is then filtered through dry filter paper. The ether isremoved by distillation and filtration, leaving a heterogeneous residuefree from the residual tarry pitch, and containing various hydrocarbonand cresolic and phenolic substances. By fractionation with heat, orsteam distillation from an alkaline solution, this residue may be:

further refined and purified, asthese hydrocarbons and phenolic and likesubstances may be separated and extracted by suitable solvents, but forpractical use, the ether-soluble product is sufliciently purified to befree from the objectionable features attendant the use of crude coal tarand without loss or diminution of its therapeutic properties whendiluted in various strengths and mixed with substances commonly used inointment preparations for cutaneous in- 10 fiammations, such as zincoxide, petrolatum and starch. As an example of such a composition, andthat which I have found to be most efiicacious for infantile eczema, Itake, by weight:

0f the above-described Parts Ether-soluble tar distillate 3Pulverizedzinc oxide 30 Starch 50 Yellow petrolatum 20 It is foundimportant to mix the distillate thoroughly before adding toit the otheringredients and to incorporate it evenly with the ointment vehicle.

As the therapeutic'principle which I have described is a fraction andnot an entity, it is difficult to specify its constants with exactness.The product is a semi-solid, oily, yellow-colored, ethersoluble phenolicand hydrocarbon substance, volatile at a. temperature lower than 200 C.and capable of distillation with steam at 100 C. at atmosphericpressure.

In the foregoing description where I have specified the primarydistillation by passing through the hot solution of crude coal tar arapid stream ofsteam until no more oil appears in the distillate, I wishit to be understood that such specification of the use of steam is ofthe method which I have practiced preferentially; but that suchdistillation may be effected by heat from any other source, as by drydistillation, the effective temperature being kept below 200 (3., sincethis effective temperature will remove by volatilization the substancesdesired, with boiling points up to 200 C. I wish it also understood thatwhere I have specified that the fraction obtained from such primarydistillation is to be redistilled in the presence of steam, that suchfraction, with boiling points up to 200 0., is redistilled in thepresence of steam at a temperature of approximately 100 C. atatmospheric pressure.

Having thus described my invention, I claim:

1. A medicinal preparation, for the treatment of eczema, containing theether-soluble fraction of the coal-tar distillate resultant at about butbelow 100 C., which fraction distils in the presence of steam at atemperature of approximate- 1y 100 C. at atmospheric pressure.

2. A medicinal preparation for the treatment or infantile eczema,containing the homogenous ether-soluble extract of the redistilledfraction of crude coal-tar which is steam-volatile at 100 C. atatmospheric pressure incorporated with an ointment vehicle containingpulverized zinc oxide and/or starch.

3. A medicinal preparation for the treatment of cutaneous inflammationof eczematous origin consisting of an ointment vehicle containing a.minor percentage of the ether-soluble extract of the redistilledcoal-tar distillate which is volatile at a temperature aproximating butbelow 200 C. and capable of distillation in the presence of steam at 100C.

- ARNOLD E. OSTERBERG.

